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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Aleph Johnston-Bloom  
Friday, January 1st 2016
Created: Jan 1st 4:09 am
3 Considerable Alpine / Above 2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
3 Considerable Treeline / 1,000'-2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
2 Moderate Below Treeline / Below 1,000' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
 Show the Complete North American Avalanche Danger Scale
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Special Announcement

Happy New Year! Filing for the PFD today? Remember The Friends of the CNFAIC is part of PICK.CLICK.GIVE. Your donations are greatly appreciated and integral to making the CNFAIC possible and sustainable. 

Did you make a resolution to get avalanche education in 2016? FCNFAIC is now accepting applications for TWO NEW scholarships! Both scholarships are for avalanche education up to $500. One will be awarded to a snowmachiner and the other to a skier or non-motorized user.

 Please include in your application: name, mailing address, your financial need and how you plan to spread avalanche awareness to your community post-award.  Applications due by 10PM on January 6th.  Please send your applications to chugachavyfriends@gmail.com

The Friends-CNFAIC board looks forward to hearing from you! 


The Bottom Line

CONSIDERABLE avalanche danger exists both at Treeline and in the Alpine where human triggered windslabs 1-4’ thick are likely on steep wind loaded features. The storm coming in today will bring new snow, rain and wind adding load and building sensitive storm slabs. Natural avalanches will be possible. Cautious route-finding and conservative terrain choices will be important.  Conditions may change rapidly in the afternoon into the evening, when the precipitation instensity is forecasted to be the heaviest. 

MODERATE avalanche danger exists below 1000’ where a larger avalanche from above could run into this elevation band.


Primary Concern

After a break in the stormy weather for most of the day yesterday we are back in it today. The first storm of 2016 could bring another 2 inches of moisture to the advisory area today and tonight as well as ramping up the winds. Rain/snow line is forecasted to be around 1800' again. There will be a variety of storm snow concerns today. Look for signs of instability while traveling: recent avalanches, cracking and whumpfing are all indications that the snowpack is becoming stressed. As always use safe travel protocols and don't linger in runout zones. 

1) Storm slab: As the new snow falls today it may not initially bond to the existing snow surface and/or be wetter and heavier. This could create sensitive slabs in much of the terrain.

2) Wind slab: Triggering a wind slab 1-4’ thick is likely on steep wind loaded features where multiple layers of wind affected snow exist. Yesterday these wind loaded areas were easy to spot due to their pillow-like shape, but today another 10” of snow is expected and Easterly winds 30-50 mph will be transporting more new snow on top, thus adding additional stress to the snowpack and the potential for more wind slabs.

3) Cornices: With such strong winds and warm snow at ridgetops, we can expect cornices to be tender. These 'backcountry bombs' are likely to trigger a wind slab or step down to a deeper instability. Avoid ridgelines with large cornices and don’t put yourself below one.

4) Wet loose avalanches: More rain on snow will saturate the upper layers of the snowpack below 1800’. This is more of a concern in areas with terrain traps and in steep channeled terrain where an avalanche from above will be impossible to escape. 

Wind effected snow in Hippy Bowl yesterday: cornices, wind-pillows and sculpted ridgelines will all change with the additional snow and wind today. 

 


Secondary Concern

The Thanksgiving Rain Crust (TRC)/small facet combo is getting more and more deeply buried but continues to be on our radar as a concern. Yesterday we received additional reports of avalanches breaking into older weak snow primarily in the periphery of our advisory area. As the snowpack gets yet another load we will be monitoring whether slides are breaking in old snow on this persistent weak layer. Cautious travel is already advised. Deep slab potential is another reason to not put more than one skier/rider or sledder on the slope in avalanche terrain and to watch out for thin spots where triggering may be easier. 

Pit from Tincan 2300', SW aspect. Note: facets over the TRC buried over 3' deep.

 


Mountain Weather

Yesterday skies mostly cleared after a burst of precipitation favoring the Girdwood Valley in the early morning. Temperatures were in the mid 20Fs at ridgeline and warmer in the valleys. Winds were easterly and blew 10-20 mph throughout the day.

Clouds increased overnight as the next storm moved into the region. Today will be overcast with rain/snow falling. 5-10 inches of snow is forecasted for the mountains today. Rain/snow line should be approximately 1800'. Easterly winds will increase to 30-50 mph this afternoon. Temperatures will be in the high 20Fs-mid 30Fs. The storm will continue overnight with an additional 3-12 inches of snow forecasted to fall. The rain/snow line will be dropping as temperatures cool slightly. 

Rain/snow showers will continue through the weekend as the active pattern persists. The series of Low pressure systems continue to move into the Gulf in conjuntion with a moisture plume being pushed over the area by the jet. 

 

PRECIPITATION 24-hour data (6am - 6am)

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 30   1 .1  71 
Summit Lake (1400')  32  0  0 18 
Alyeska Mid (1700')  31 4.5 .54  59 

 

RIDGETOP 24-hour data (6am - 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 23  ENE   20 52 
Seattle Ridge(2400') 25  n/a n/a  n/a 

This is a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (this advisory does not apply to highways, railroads, or operating ski areas).

Winter snowmachine use open/closed status and riding conditions updates

Riding status is not associated with avalanche danger. An area will be open to motorized use in accordance to the Forest Management Plan when snow coverage is adequate to protect underlying vegetation. Backcountry hazards including avalanche hazard are always present regardless of the open status of motorized use areas.

(Updated: May 16, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedThanks all for a safe and fun season on the Chugach NF! Stay tuned for the 2017/18 season. #playsafe #snowtosealevel
Twentymile: Closed
Seward District
Carter Lake: Closed
Lost Lake Trail: Closed
Primrose Trail: Closed
Resurrection Pass Trail: ClosedResurrection Pass trail will be open to snowmachine use during the 2017/18 winter season.
Snug Harbor: Closed
South Fork Snow River Corridor: Closed
Summit Lake: Closed

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The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur. This advisory provided by the Chugach National Forest, in partnership with Friends of the Chugach National Forest Avalanche Information Center.


USFS SNOW AND AVALANCHE HOTLINE (907) 754-2369
If you have comments or questions regarding CNFAIC operations or winter recreation management, please email staff@chugachavalanche.org
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